Carburetor



Oct. 4, 1932. w. s. CARLISTON C'ARBUI'RE'IOR Filed July 2, 1928 2 Sheets-Sheet l 'z'zvsj-z 5.2- ZVzlZZa'am 6'. Carleton.

Oct. 4, 1932. w, 5 (:ARLSTON 1,880,791

CARBURETOR Filed July 2, 1928 2 Sheets-Sheet 2 (flZZZz am 6. Carlst'on.

Patented Oct. 4, 1932 UNITED STATES PATENT OFFICE WILLIAM. s. CABLSTON, or xoxomo, INDIANA, ASSIGNOR r0 KINGSTON rnonuo'rs CORPORATION, or KOKOMO, INDIANA, A CORPORATION or INDIANA CARBUBETOR Application filed July 2,

This invention relates to carburetors and is particularly concerned with the provision of improved accelerating means with an automatic control therefor whereby the desired mixture ratio is maintained throughout the range and under variable conditions of operation without objectionable change of operation of the engine at transition points where the various mixture supplying instrumentalities of the carburetor become operative.

In carburetors of the general type under consideration the additional mixture requirements necessary for engine acceleration are supplied from a supplemental fuel chamber known to the art as an accelerating well. Such chambers are ordinarily open to atmosphere and the walls thereof are provided with a series ofmetered air openings to supply the desired additional air for acceleration as the well is emptied by the suction draft thereon. These structures have been objectionable in that the well often emptied too early in the range or so suddenly that the operating mixture became deranged causing irregular or faulty operation of the engine.

It is an important object therefore of the present invention to provide a carburetor structure wherein the accelerating well is closed to atmosphere during a predetermined position of the range of operation.

It is a further important object of this invention to provide throttle controlled means for rendering the accelerating well inoperative until the throttle has been opened a predetermined amount. I V

, It is another important .object of this inventionto provide a carburetor-having an accelerating well which is normally closed to atmosphere with means for automatically opening the same to atmosphere during a predetermined position of the range of operation.

It is finally an important object of this invention to provide a carburetor which is simple in construction,economical to manufacture and wherein the mixture supplying instrumentalities are so arranged, proportioned and controlled as to provide an effective eco- 1928. Serial No. 289,645.

nomical mixture throughout the range of operation.

Other and further important objects of this invention will be apparent from the disclosures in the specification and the accompanying drawings.

The invention (in a preferred form) is shown on the drawings and hereinafter more fully described.

On the drawings:

Figure 1 is a side elevation of a carburetor embodying the principles of this invention.

Figure 2 is a central longitudinal section thereof with parts shown in dotted lines.

Figure 3 is a top plan view of the carburetor of Figure 1 showing the same as equipped with a slightly modified form of fuel control valve.

Figure 4 is a side elevation of the carburetor shown in Figure 3 with parts broken away to show the fuel control valve.

As shown on the drawings:

The carburetor embodying the principles of this invention which is shown for purposes of illustration in the accompanying drawings comprises. in general a fuel supply chamber 1 in which is mounted a usual float feed type of fuel control 2. Mounted on the fuel supply chamber is a body casting which is provided with an air inlet 3, controlled by .a choke valve 4, and a mixture outlet 5,

which is controlled by a usual butterfly type throttle valve 6. Situated between the mixture outlet and the air inlet is a Venturi member? into the throat of which projects a tube 8 through which carburetted air is carried to the interior of the Venturi member in a manner which is well known in the art. A passaged boss 9 extends downwardly from the body casting into the fuel supply chamber and communicates with said chamber through a passage 10. Said boss 9 is provided with an axial passage 11 in which a fuel nozzle 12 extends, said nozzle having its open end projecting into the lower end of the tube 8 and being spaced from the walls of said tube.

Flow of fuel into the passage 11 is controlled by an adjustable needle valve 13 which serves to effect the main high speed operating adjustment. v I

7 well, a series of holes 14; in the nozzle 12 affording communication between the well and the lnterior of the nozzle below the normal fuel level. As is usual in sucheonstructions, withdrawal of fuel from the well successively uncovers the holes 14 thus admitting required additional air as the desired acceleration is attained and when the well is subjected to atmosphere or a higher pressure than that existing within the carburetor; Atmospheric connection to the well at a point below the normal fuel level in the chamber and Well is afiorded by a passage 15 which opens to atmosphere at 16.

Interposed betweenthe passage 15 and the opening 16 is a valve 17 slidably mounted in a well 17 in a boss 17 on the body casting. The valve 17 is normally seated to close the passage 15 by a spring 17 mounted on the valve pin 17 a in the boss 17*.

The throttle valve shaft 6 which projects beyond the body casting is provided at its outer end with a usual operating lever 18 rigidly secured thereto and having a downwardly projecting boss 19 secured relatively shaft 6 at a desired angle. Loosely mounted on the outer end of the shaft 6 there is also a crank arm 20 which is connected through a suitable linkage 21 with the stem 17 of the valve 17. This connection permits of an initial movement of the throttle valve through a predetermined angle without opening the valve 17 and the passage 15, 16. When, however, the throttle shaft has been moved a predetermined amount the boss 19 engages the crank arm 20 and the valve 17 is lifted to open the passage 15, 16. This operation, which of course, renders the accelerating well effective, is shown in dotted lines in Figure l.

The upper end of the accelerating well communicates with the interior of the tube 8 and with the air inlet chamber through a series of holes 22 in the base of said tube 8 so that when the passage 15, 16 is open an air lift is exerted on the carburetted mixthe same is closed or nearly closed. For this purpose an idling tube or passage 23 is pro vided which communicates at its lower end with the accelerating well through a metered opening 24:. The passage 23 communicates at its upper end with a series of holes 25, '26, 27 which open both above and below the edge of the throttle 6 when the same isin closed or nearly closed position and thus admit mixture for idling or low speed operation into the mixture outlet 5. The quality of this mixture is controlled by an air bleed hole 28 in the tube 23 and also by the admission of mixture through a passage 29 in the wall of the Venturi member 7. This passage 29 communicates with a passage 30 and thence with the interior. of the idling tube or passage 23 through a metered passage 31 which is controlled by an adjustable valve 32 which efiects the operating idling adjustment. v

Figures 3 and ishow a novel form of main fuel supply valve adjustment which I have provided. In this construction, the fuel valve is replaced by a valve 33 of the needle'valve type which seats downwardly in apassage 34 affording communication between the fuel supply chamber and the nozzle 12. Said valve 33 is slidably mounted in a boss on the body casting and is held off and away from its seat by a spring 35. The upper end of the stem of the valve 33 is bifurcated as at 36-to afi ord a flatsurface 37 which cooperates with the end of an axially movable threaded member 38 which is angularly mounted-in a threaded boss on the body casting. Thus when the member 38 is rotated in one direction the end thereof will move across the flat surface 37 and force the valve 33 towards its seat and when rotated in the opposite direction will permit 'thevalve 33 to be moved away from its seat by the spring 35. The end of the threaded member 38 is provided at .39 with a suitable connection for a dash operating connection (not shown). v

It will be apparent from the foregoing that this invention provides a carburetor of simple and economical construction which is adapted to provide an effective and economical operating mixture throughout the range of operation. By providing a closure for the atmospheric passage to the accelerating Well proper, operation upon gradual opening of the throttle is not disturbed and upon sudden or complete opening of the throttle the operation functioning of the well'becomes effective for the purpose desired. r I

Furthermore the'provision of a controlled atmospheric passage to the well and positioning the same towards the upper end of the nozzle provides the desired air lift and also properly dilutes the mixture to afford economy of operation during high speed or open throttle conditions. 7 r y I am aware that numerous details of construction may be varied through a wide range without departing from the principlesof this invention, and I therefore do not purpose limiting this applicationotherwise than necessi'tated by the prior art.

I claim as my invention; 1. In a carburetor, a source of fuel supply, a main air inlet, a mixture outlet, a throttle comprising a butterfly valve and a shaft therefor, a fuel nozzle, an accelerating Well communicating with the nozzle, an air inlet to said accelerating Well and means of controlling said inlet, said means comprising a boss integrally formed on the body of said carburetor, a Well in said boss, a passage connecting said vWell and said accelerating Well,

an opening connecting said Well With the atmosphere, a valve in said Well, a stem on said valve, a spring on said stem normally seating said valve to close said passage, a loosely mounted crank arm on said throttle shaft, connecting links between said valve stem and said arm, and a boss on said shaft to engage said crank arm to open said valve after the throttle has been opened a predetermined amount.

2. In a carburetor having an accelerator Well and an air inlet thereto, throttle controlled means for opening said inlet a predetermined period after said throttle is opened, said means comprising a spring seated valve normally closing said inlet, a loosely mounted crank arm on said throttle connected to said valve, and a boss on said throttle to raise said crank arm and open said valve.

In testimony whereof I have hereunto subscribed my name.

WILLIAM S. CARLSTON. 

